Buttonweed (Diodia teres var. teres)

Life history

Species overview

Buttonweed (Diodia teres var. teres), a State Special Concern plant, is found on sandy terraces along the Wisconsin River. Blooming occurs early July through early September; fruiting occurs early August through late October. The optimal identification period for this species is late June through late October.

Synonyms: Diodia teres, Diodia teres var. setifera

Identification

Distinguishing characteristics: Fruit much surpassed by the long (6 to 10 mm) stipules.

Flower characteristics: Sessile in many of the upper axils; sepals 4, lanceolate; corolla funnel-form, white to pink or pale purple.

State status

The table below provides information about the protected status -
state and federal - and the rank (S and G Ranks) for Buttonweed
(Diodia teres var. teres). See the Working
List Key for more information about abbreviations. Counties shaded
blue have documented occurrences for this species in the Wisconsin
Natural Heritage Inventory database.
The map is provided as a general reference of where this species has
been found to date and is not meant as a range map.

Summary Information

State Status

SC

Federal Status in Wisconsin

none

State Rank

S1

Global Rank

G5T5

Tracked by NHI

Y

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

Habitat description: Found on sandy terraces along the Wisconsin River.

Soils: Dry or sandy soils.

Natural communities

This table lists the natural communities that are associated with Buttonweed. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Buttonweed (Diodia teres var. teres) has very few known occurrences in the state and is of the highest priority for conservation; we encourage you to consult with your District Ecologist or NHI Botanist for specific recommendations for your site.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.